Oil burner pump unit with air purging means



Sept. 20, 1966 R. w. ROPER 3,273,513

OIL BURNER PUMP UNIT WITH AIR PURGING MEANS Filed April 28, 1965 2Sheets-Sheet 1 Sept. 20, 1966 R w. ROPER 3,273,513

OIL BURNER PUMP UNIT WITH AIR PURGING MEANS Filed April 28, 1965 2Sheets-Sheet 2 United States Patent ice 3,213,513

3,273,513 OIL BURNER PUMP UNIT WITH AIR PURGING MEANS Raymond W. Roper,Rockford, Ill., assignor to Sundstrand Corporation, a corporation ofIllinois Filed Apr. 28, 1965, Ser. No. 453,558 11 Claims. (Cl. 103-203)This application is a continuation-in-part of my copending applicationSerial No. 430,095, filed February 3, 1965, now abandoned.

This invention relates to pumps, and especially oil burner pumps, andmore particularly the invention relates to an oil burner pump unit withimproved means for purging air from the unit as on starting operationfollowing installation or shutdown.

It is a general object of the invention to provide a new and improvedpump unit of the type described.

Another object of the invention is to provide a pump unit of thecharacter mentioned with a new and improved manually controllable airpurging valve.

A more specific object is to provide in a pump unit of the typedescribed a new and improved air purging valve in the form of athreadably adjustable plug member mounted in the unit housing andcommunicating with the outlet of a pump in the housing, including meansproviding a restrictive annular passage limiting the flow of oil aspurging is completed, in series ahead of a radial port in the plug, anda longitudinal passage through the plug of substantially greatercapacity than the annular restrictive passage for purposes of reducingthe velocity of fluid to provide a controlled relatively weak spout ofoil on completion of purging.

While units of the character mentioned are often referred to as pumps,they usually involve more than a pump per se. More particularly, in thetypical unit, there is a suitable housing in which a pump is mounted tohave an inlet adapted for communication with a source of oil and anoutlet adapted to deliver fluid under pressure to a pressure responsivevalve which establishes communication between the pump outlet and aburner port in the housing adapted to be connected with a suitableburner. On starting such equipment in operation, initially after firstinstallation or after shutdown, as where the tank has run out of oil andbeen refilled, the passages communicating with the pump inlet, and withthe outlet, are not always completely filled with oil so that for somelimited period of time after starting, the pump functions merely to pumpair. While it is necessary to remove such air from the system beforepure oil can be delivered, it is undesirable to pump air or mixed airand oil to a nozzle at the burner as such conditions contribute to animproper ignition of the burner flame and/ or poor combustion which hasundesirable side eifects.

Accordingly, in the past, it has been conventional to provide a purgeport in the housing communicating with the pump outlet and normallyclosed during usual operating conditions, but operable on start-up topermit the pump to discharge air ahead of the valve controlled burnerport until such time as air-free oil flows from the purge port,whereupon the latter may be again closed and flow to the burner port iscontrolled by the pressure responsive valve. While such purge ports haveeffectively served to rid the system of air, there have beendisadvantages. For example, the pump is capable of developing asubstantial pressure so that when the air is purged and the oil startsto flow from the purge port in an uncontrolled manner, it may be capableof spouting completely across the room in which the pump is installed.While there have been some attempts to control the discharge of oil oncompletion of air purging, before the purge port is closed, suchattempts have generally enjoyed Patented Sept. 20, 1966 poor receptionbecause of unacceptable limitations. For example, in some cases thepurge valving has been complex and expensive. In other situations, flowlimiting restrictions have been so minute as to be difficult ofmanufacture and easy of plugging. Some have provided a fixed laterallydirected purge outlet which may be appropriately aimed if the pump ismounted in one position but inappropriately aimed if the pump isinverted.

With the above considerations in mind, it is an object of this inventionto provide a new and improved purge means in which the discharge isproperly directed at all times whether the unit is inverted or obverted,wherein the oil rate of flow on completion of purging is limited to acontrolled relatively weak spout, and wherein the flow limiting passagesare restrictive enough and at the same time not subject to obstructiveclogging due to dirt and the like.

Other objects and advantages will become readily apparent from thefollowing detailed description taken in connection with the accompanyingdrawings, in which:

FIG. 1 is a transverse cross section of a pump unit embodying thepresent invention, taken at about the line 11 of FIG. 2;

FIG. 2 is a longitudinal sectional view of the unit taken at about theline 22 of FIG. 1, FIGS. 1 and 2 showing the pressure responsive valveand the purge valve positioned for purging; and

FIG. 3 is a diagrammatic view of the pump circuit with the pressureregulating valve and the purge valve in condition for normal burneroperation and with the pump proper omitted from the housing forsimplicity.

While an illustrative embodiment of the invention is shown in thedrawings and will be described in detail herein, the invention issusceptible of embodiment in many different forms, and it should beunderstood that the present disclosure is to be considered as anexemplification of the principles of the invention and is not intendedto limit the invention to the embodiment illustrated. The scope of theinvention will be pointed out in the appended claims.

Referring now in more detail to the drawings, a casing is provided inthe form of a housing member 10 and an end cover 11 appropriately boltedtogether as by means 12, for example, and forming an internal chamberproviding a reservoir 14. The housing member 10 is provided with anextension 16 appropriately supporting a pump drive shaft 18, andadjacent the end of the extension 16, the shaft 18 is surrounded by ashaft seal generally designated 20 to prevent leakage from the housingof fluid progressing along the shaft from the pump.

The shaft 18 extends into the reservoir 14 and is drivingly connected toa crescent gear pump 22. The pump 22 is mounted in a housing provided bya plate 23 at one side (the right side as in FIG. 2), a plate 24 at theleft side, and a surrounding ring 25. Within the ring 25 and between theplates 23 and 24 there is an internally threaded ring-shaped gear member28 meshing with an eccentric externally toothed gear member 29 on shaft18. Within the space between the gear members 28 and 29 there is acrescent shaped fixedly mounted member 30. The members 23, 24 and 25 areappropriately secured to the housing member 10 as by means 32. On theexposed side of the plate 24 there is a vibration damping capsule as at33.

The reservoir 14 is adapted to be connected with a suitable source offuel oil as through an inlet at 34 or 34' in the form of a threaded portshown in FIG. 1 with a removable plug as at 34". Preferably, the pump 22is surrounded by a filter 35 including a cylindrical screen 36 and anend plate closure 37 carrying a spring means 38 biasing the opposite endof the cylindrical screen against the housing member at the opposite endof the reservorr.

In operation, the arrangement is such that on rotation of the driveshaft 18, the pump 22 is effective to draw oil from the source such as atank into the reservoir through inlet 34 and into the pump through anappropriate inlet inside the confines of the filter 35 as illustrateddiagrammatically at 40 on FIG. 3. The pump discharges fluid underpressure through an appropriate out let 41 communicating with a pressureresponsive valve 43 in the housing member 10.

The valve 43 is mounted in a bore 44 and includes a stationary sleevemember 45 which receives a slidable valve member 46. The upper end ofthe bore 44 (FIG. 3) is closed by threaded plug member 47 having burnerport 48 adapted to be connected with a burner nozzle or the like, andthe plug 47 terminates in a raised seat 49 against which the closed endof valve member 46 is biased by a spring 50. The spring is seated in aclosure plug 52 at the opposite end of bore 44 including an appropriatespring pressure adjusting screw 53 covered by a cap 54.

Valve member 46 is movable from the position illustrated in FIG. 1,closing the burner port, to a position illustrated in FIG. 3, openingthe burner port to communicate with the pump outlet, and the valvemember is normally biased to the port closed position by means of spring50. Upon operation of the pump 22, with the purge port closed pressurebuilds up in the passage 41 to move the valve member 46 to port openposition.

The sleeve member 45 is provided with one or more longitudinal slots asat 58 which communicate the passage 41 with a reduced portion 59 on thevalve member between valve lands 60 and 61, In order to assure rapidvalve closure on shutting down the pump, land 61 includes a longitudinalbleed slot 63 which allows a limited amount of fluid to pass to thereduced portion 64 of the valve member, and the latter communicatesthrough a sleeve port 65 with a by-pass or return passage 67.

In operation, as pump outlet pressure builds up, and the valve member 64moves to the valve open position illustrated in FIG. 3, groove 59 in thevalve member communicates with a by-pass or return port 68 in the sleeve45, in turn communicating with the passage 67, so that fluid in excessof that required at the nozzle may be returned to the reservoir 14through the passage 67 and a threaded inlet port 70 adjacent the chamber14.

If desired, a closure plug 72 may be removed from the housing member 10,and a closure plug may be inserted in the port 70 to permit return ofexcess fluid to the source tank connected to port 73 in place of plug72.

Leakage fluid is returned from the shaft seal 20 to the reservoir 14through a passage as illustrated at 75 leading to the bore 44 andcommunicating with the interior of the sleeve 45 and the hollow interiorof the valve member 46 through a sleeve port 76. The interior of thevalve member communicates with a groove 64 through a radial port 77.

According to the present invention, in order to purge air from the pumpsystem on start-up, the valve chamber 80 adjacent nozzle port seat 49communicates with a purge port 81 leading to a purge chamber 82, and atthe entrance of the port 81 to the chamber 82 there is a valve seat 83.The chamber 82 leads to the outside of the pump housing member 10 andterminates in a relatively long straight threaded portion as at 85, andis adapted to receive a purge valve member 87 in the form of an elongategenerally cylindrical plug member having a reduced end portion 86 in thechamber 82 adjacent port 81, land a threaded external portion 88adjustable in the threaded receptacle 85.

The reduced end portion of the purge valve member terminates in avalving portion 90 adapted to seat at 83 to close the purge port 81 asshown in FIG. 3 and adapted to be adjusted to open the purge port asshown in FIG. 2.

The valve member 87 includes an enlarged polygonal flange 92facilitating manual adjustment and terminates externally of the housingin a nipple end adapted to receive a rubber hose or the like, ifdesired, though no hose is necessary with a controlled discharge asprovided by the present invention. Member 87 includes a centrallongitudinal passage 94 of substantial proportions, leading from theouter terminus to the vicinity of the reduced end portion 86 andcommunicating through a radial port 95 with a restrictive annularpassage 96 between the surface of the reduced portion 86 and the wall ofthe chamber 82.

In operation, when the valve member 87 is manually adjusted to open thebleed port or purge port 81, as shown in FIG. 2, the pump outlet isconnected to atmosphere through passage 41, port 81, chamber 82, annularpassage 96, radial port 95 and longitudinal passage 94 so that air maybe discharged from the system to atmosphere without opening the burnerport 48, and such communication is normally continued after some oilflow begins, until such time as air-free oil flows. In order to restrictthe volume of oil that may be discharged, upon completion of :airpurging, the annular passage 96 provides 'a restriction limiting flow toa volume less than that which might in fact be accommodated by the port95 and the passage 94. The radial port 95 may thus be made of relativelylarger proportions than otherwise would be possible in order tofacilitate manufacture and in order to reduce the likelihood ofobstructive clogging, The still larger proportions of passage 94 allow areduction in the velocity of flow from the terminus of the valve member.At the same time, while the annular passage 36 limits the amount offlow, its relatively great circumferential extent reduces the likelihoodof clogging, and the tolerances of the restriction may be adequatelycontrolled by controlling the dimensions of the reduced portion 86 andof the chamber 82.

In an actual construction which has operated satisfactorily, the outerdiameter of the reduced portion 86 is .318, the radial thickness of theannular passage 96 is on the order of .01", and the radial port has adiameter of .062". It will be understood that so long as the radialthickness of the annular passage 96 is less than approximately theradius of the radial port 95, the annular passage constitutes thecontrolling restriction. In the example given the eifective area of suchrestriction may be considered as .01 times the circumference of the .062diameter radial port.

The axis of the purge plug and its longitudinal passage 04 is parallelto the shaft axis so that oil is always directed axially of the unitregardless of the angular disposition of the unit about the axis of theshaft when mounted. Mounting is usually facilitated by appropriatemounting flanges associated With housing member 10. The constantdiameter of housing threads and plug threads 88 throughout their lengthallows adjustment of plug 87 while maintaining a seal in all adjustedpositions, and at the same time allows removal of the plug for insertionof a pressure gauge fitting with a tapered pipe thread.

While the invention has been illustrated in connection with a singlestage unit, it will be understood that it may be embodied in a two-stageunit in which the first stage draws oil from the tank to the reservoirand returns the excess to tank, and the second stage pumps oil from thereservoir to the pressure regulating valve, with the excess alsoreturning to tank or to the reservoir.

It will be understood that for the purpose of orderly collection of thefluid discharged from the passage 94 upon completion of purging, the oilshould flow in a neat, steady stream rather than discharge in a spray orthe like. While the oil may tend to be atomized into a spray in travelthrough the narrow annular passage 96, discharge may be formed into asuitable stream, utilizing a Single radial port 95, by suitablycontrolling length of the longitudinal passage 94.

\More specifically, if the length of the longitudinal passage is tooshort, with a single radial port 9 5, there may be some tendency for theoil discharge to spray rather than to flow. On the other hand, with asingle radial port 95, the oil discharged may be controlled to asuitable stream by making longitudinal passage 94 of sufficient lengthto cause collection of the spray and formation of a smooth, even stream.

Alternative to controlling the discharge to form a stream rather than aspray by elongating passage 94, it has been found that the length of thepassage 94 may be significantly shortened, while still discharging astream by providing a second radial port as at 95' opposed to the firstport 915. By this provision, the fluid entering from the two portscollides and the collision assists in reducing any spray to the form ofa stream. As an example, radial port 95' may be of the same dimensionsas the port 95, with other dimensions as in the example given above,where the length of passage 94 is about .967.

'1 claim:

1. In an oil burner pumping system, a casing, means providing an inletto the casing adapted for connection with a source of burner oil, adrive shaft mounted in the casing, a pump in the casing driven by saidshaft, having a low pressure intake communicating with said inlet andhaving a high pressure outlet, means providing a burner port in thecasing adapted for connection with an oil burner, a discharge passage inthe casing connecting the high pressure outlet and the burner port, apressure responsive valve in the discharge passage adapted to establishcommunication between the high pressure outlet and the burner port uponthe buildup of a predetermined discharged pressure, air purging meanscomprising a port in the casing communicating with said passage, acylindrical recess in the casing communicating with said purge port andopening to the exterior of the casing, a manually operable air purgeplug threadably adjustable in said recess, said plug comprising acylindrical member having a re duced inner end portion slightly spacedfrom the recess wall and providing between the wall and the reducedportion a restrictive annular passage, a valving surface on the reducedend portion cooperable with said bleed port and movable relative to thebleed port upon threadable adjustment of the plug between a port closedposition and a port open position, a longitudinal passage through theplug member from the exterior of the casing to the vicinity of thereduced end portion, and a radial port in the plug member connectingsaid annular passage and said longitudinal passage.

2. A combination as defined in claim 1, wherein the axis of the purgeplug and the longitudinal passage therein are disposed parallel to theaxis of the drive shaft so the spout of oil from the longitudinalpassage is directed axially of the casing regardless of the angulardisposition of the casing about the axis of the shaft when mounted.

3. A combination as defined in claim 1, wherein said annular passage hasa radial thickness less than the diameter of said radial port.

4. A combination as defined in claim 1, wherein the product of theradial thickness of the annular passage and the circumference of theradial port are less than the area of the radial port.

5. A combination as defined in claim 4, wherein the longitudinal passagein the plug provides a relatively large [flow area compared to theeffective flow area of the annular passage so as to reduce the velocityof fi-uid flowing outwardly from the plug to a controlled rate producinga weak spout.

6. A combination as defined in claim 1, including at least oneadditional radial port in the plug member connecting said annularpassage and said longitudinal passage and opposed to the first recitedradial port.

7. A combination as defined in claim 1, including an additional radialport in the plug member connecting said annular passage and saidlongitudinal passage disposed in opposition to the first recited radialport so that fluid entering the longitudinal passage from the opposedports collides to assist in reducing any spray to a stream, said annularpassage having an effective passage area less than the area of theradial ports.

8. In an oil burner pumping system, a casing, means providing an inletto the casing adapted for connection with a source of burner oil, adrive shaft mounted in the casing, means providing a reservoir in thecasing communicating with said inlet, a pump in the casing driven bysaid shaft, having a low pressure intake communicating with saidreservoir and the high pressure outlet, means providing a burner port inthe casing adapted for connection with an oil burner, a dischargepassage in the casing connecting the high pressure outlet and the burnerport, a pressure responsive valve in the discharge passage adapted toestablish communication between the high pressure outlet and the burnerport upon the buildup of a predetermined discharge pressure, air purgingmeans comprising a port in the casing communicating with said passage, acylindrical recess in the casing communicating with said purge port andopening to the exterior of the casing, a manually operable air purgeplug threadably adjustable in said recess, said plug comprising acylindrical member having a reduced inner end portion slightly spacedfrom the recess wall and providing between the wall and the reducedportion a restrictive annular passage, a valving surface on the reducedend portion cooperable with said bleed port and movable relative to thebleed port upon threadable adjustment of the plug between a port closedposition and a port open position, a longitudinal passage through theplug member from the exterior of the casing to the vicinity of thereduced end portion, a radial port in the plug member connecting saidannular passage and said longitudinal passage, said annular passagehaving a radial thickness less than the radius of said radial port, sothat the annular passage restricts the flow of fluid from the purge plugto a value less than that permitted by the size of the radial port.

9. In an oil burner pumping system, a casing, means providing an inletto the casing adapted for connection with a source of burner oil, adrive shaft mounted in the casing, means providing a reservoir in thecasing communicating with said inlet, a pump in the casing driven bysaid shaft, having a low pressure intake communicating with saidreservoir and the high pressure outlet, means providing a burner port inthe casing adapted for connection with an oil burner, a dischargepassage in the casing connecting the high pressure outlet and the burnerport, a pressure responsive valve in the discharge passage adapted toestablish communication between the high pressure outlet and the burnerport upon the buildup of a predetermined discharge pressure, saidpressure responsive valve including a valve member cooperating with saidburner port and movable between .a port closed position and a port openposition, and spring means biasing the valve member to port closedposition, air purging means comprising a port in the casingcommunicating with said passage, a cylindrical recess in the casingcommunicating with said purge port and opening to the exterior of thecasing, a manually operable air purge plug threadably adjustable in saidrecess, said plug comprising a cylindrical member having a reduced innerend portion slightly spaced from the recess wall and providing betweenthe wall and the reduced portion a restrictive annular passage, avalving surface on the reduced end portion cooperable with said bleedport and movable relative to the bleed port upon threadable adjustmentof the plug between a port closed position and a port open position, alongitudinal passage through the plug member from the exterior of thecasing to the vicinity of the reduced end portion, and a radial port inthe plug member connecting 7 said annular passage and said longitudinalpassage, said annular passage having a radial thickness less than theradius of said radial port, so that the annular passage restricts theflow of fluid from the purge plug to a value less than that permitted bythe size of the radial port.

10. A combination as defined in claim 9, wherein the axis of the purgeplug and the longitudinal passage therein are disposed parallel to theaxis of the drive shaft so the spout of oil from the longitudinalpassage is directed axially of the casing regardless of the angulardisposition of the casing about the axis of the shaft when mounted.

1 1. In an oil burner pumping system, a casing, means providing an inletto the casing adapted for connection with a source of burner oil, adrive shaft mounted in the casing, means providing a reservoir in thecasing communicating with said inlet, a pump in the casing driven bysaid shaft, having a low pressure intake communicating with saidreservoir and the high pressure outlet, means providing a burner port inthe casing adapted for connection with an oil burner, a dischargepassage in the casing connecting the high pressure outlet and the burnerport, a pressure responsive valve in the discharge passage adapted toestablish communication between the high pressure outlet and the burnerport upon the buildup of a predetermined discharge pressure, saidpressure responsive valve comprising means providing a valve chambercommunicating with said discharge passage and with said burner port, avalve member in the valve chamber controlling said burner port andmovable between a port closed position and a port open position, springmeans biasing the valve member to a port closed position, a by-pass portcommunicating with the valve chamber, and valving on the valve memberestablishing communication between said discharge passage and saidby-pass port on movement of the valve member to a port open position, areturn passage leading from said by-pass port to said reservoir, airpurging means comprising a port in the casing communicating with saidpassage, a cylindrical recess in the casing communicating with saidpurge port and opening to the exterior of the casing, a manuallyoperable air purge plug threadably adjustable in said recess, said plugcomprising a cylindrical member having a reduced inner end portionslightly spaced from the recess wall and providing between the wall andthe reduced portion a restrictive annular passage, a valving surface onthe reduced end portion cooperable with said bleed port and movablerelative to the bleed port upon threadable adjustment of the plugbetween a port closed position and a port open position, a longitudinalpassage through the plug member from the exterior of the casing to thevicinity of the reduced end portion, and a radial port in the plugmember connecting said annular passage and said longitudinal passage,said annular passage having a radial thickness less than the diameter ofsaid radial port, so that the annular passage restricts the flow offluid from the purge plug to a value less than that permitted by thesize of the radial port, the longitudinal passage in the plug providinga relatively large flow area compared to the effective flow area of theannular passage so as to reduce the velocity of fluid flowing outwardlyfrom the plug to a controlled rate producing a weak spout.

References Cited by the Examiner UNITED STATES PATENTS 2915,015 12/ 1959'Erickson et al 103203 X 2,931,314 4/1960 Erickson et a1 103 203 ROBERTM. WALKER, Primary Examiner.

1. IN AN OIL BURNER PUMPING SYSTEM, A CASING, MEANS PROVIDING AN INLETTO THE CASING ADAPTED FOR CONNECTION WITH A SOURCE OF BURNER OIL, ADRIVE SHAFT MOUNTED IN THE CASING, A PUMP IN THE CASING DRIVEN BY SAIDSHAFT, HAVING A LOW PRESSURE INTAKE COMMUNICATING WITH SAID INLET ANDHAVING A HIGH PRESSURE OUTLET, MEANS PROVIDING A BURNER PORT IN THECASING ADAPTED FOR CONNECTION WITH AN OIL BURNER, A DISCHARGE PASSAGE INTHE CASING CONNECTING THE HIGH PRESSURE OUTLET AND THE BURNER PORT, APRESSURE RESPONSIVE VALVE TO THE DISCHARGE PASSAGE ADAPTED TO ESTABLISHCOMMUNICATION BETWEEN THE HIGH PRESSURE OUTLET AND THE BURNER PORT UPONTHE BUILDUP OF A PREDETERMINED DISCHARGED PRESSURE, AIR PURGING MEANSCOMPRISING A PORT IN THE CASING COMMUNICATING WITH SAID PASSAGE, ACYLINDRICAL RECESS IN THE CASING COMMUNICATING WITH SAID PURGE PORT ANDOPENING TO THE EXTERIOR OF THE CASING, MANUALLY OPERABLE AIR PURGE PLUGTHREADABLY ADJUSTABLE IN SAID RECESS, SAID PLUG COMPRISING A CYLINDRICALMEMBER HAVING A REDUCED INNER END PORTION SLIGHTLY SPACED FROM THERECESS WALL AND PROVIDING BETWEEN THE WALL AND THE REDUCED POR-